The present invention relates to a radio frequency coil front end interface system for magnetic resonance scanners. The invention finds particular application in conjunction with an intelligent detection and recognition system for identifying and retrieving data associated with a radio frequency imaging coil. The invention will also find application in conjunction with spectroscopy, cable connection and interface systems for radio frequency coils and the like.
Horizontal or bore-type magnetic resonance imagers commonly include a bore dimensioned to receive a patient to be imaged. The bore is surrounded by a magnet assembly for generating a temporally constant magnetic field axially through the bore. Whole body radio frequency and gradient coils typically surround the bore. A patient couch supports and transports the patient into and out of the bore. More specifically, the patient couch is commonly height adjustable. The patient support surface is retractable from the bore for positioning the patient therein and extendable into the bore.
Analogously, in vertical field or open magnetic resonance imagers, pole pieces are typically positioned above and below the patient. Magnetic coils are associated with the poles to create a temporally constant field vertically between them. Gradient field and radio frequency coils are typically mounted to the pole structures.
When doing localized scans such as head or heart scans, a distinct localized coil is commonly positioned closely adjacent the patient. Cables, typically coaxial cables, are connected between the coil and a radio frequency receiver and/or transmitter.
One known technique to determine what type of coil is in a machine discloses a coil (specifically, a head coil) with an 8-pin connector. A selected one or a selected pattern of the pins are connected to ground to provide an 8bit binary identification of the insertable coil. A digital circuit reads which pins are and are not shorted to ground as 1""s and 0""s and uses digital logic to indicate to the computer the type of coil installed.
One disadvantage of this system is that it is very complex to manage a multiple conductor cable because it is large and prone to pick up stray radio frequency signals. Moreover, if one of the wires or contacts fails, an incorrect indication of the type of the installed coil is provided to the computer. This erroneous indication of the installed coil could cause an imaging sequence to be initiated which could injure the patient or cause damage to the magnetic resonance equipment.
Another disadvantage of this type of a system is the limited amount of data located on the coil, specifically 8 bits. To determine all of the potentially needed attributes of a coil, for example, model number, number of operating modes including details for each, particular decoupling voltages and the like, resort is typically made to a look-up-table accessible to the processor. In other words, the data for the coil is not resident on the coil itself, making upgrades and changes difficult.
Another known technique to determine which one of a plurality of coils is in a MR machine uses a resistive element at a plug or interface between the RF coil and the processor. Accordingly, when the coil side plug is inserted into the MR system receptacle, the processor can determine the resistance, and then determine the inserted coil based on a known relationship between resistance and coil type. Undesirably, this technique can only distinguish a relatively small number of discrete coil types. Further, once the resistive value is determined the processor must still resort to a lookup table, typically resident on the system side of the MR machine, to ascertain operating modes and characteristics.
Yet another technique to distinguish between a variety of coils potentially usable in a machine involves a microprocessor system buried within the coil side of the system. The microprocessor based solution also suffers from several undesirable aspects such as: 1) An additional line required for providing power to the processor; 2) Additional support components, like voltage regulators, decoupling and/or filtering capacitors, etc., and a printed wiring board on which to mount them; 3) The inherently ferrous nature of the packaging materials of processors, which can lead to localized distortion of the main magnetic field; and 4) All the inherent problems associated with suppressing and/or eliminating the EMI noise generated by the local oscillator which provides the main xe2x80x9cclockxe2x80x9d for the processor.
The present invention contemplates an improved attribute storage system which overcomes the above-referenced problems and others.
In accordance with one embodiment of the present invention, a magnetic resonance imaging apparatus includes an imaging coil selectively connectable to a processor through a plug and socket assembly. The plug and socket assembly has a proximal component on the coil side of the assembly, and a distal component on the processor side of the assembly. A memory device is affixed to the proximal component of the plug and socket assembly for storing data attributes particular to the image coil.
In accordance with another aspect of the present invention, the proximal component includes a substantially non-conductive housing having a plurality of channels defined therethrough. At least one connector is disposed within selected ones of the channels and a corresponding number of data leads, electrical or optical, are affixed to the connectors. An electrical or optical conductor is disposed within a remaining channel and is in communication with the memory device.
In accordance with another aspect of the present invention, the distal component includes a substantially non-conductive housing adapted to engage with the housing of the proximal component. Matching connectors are disposed within channels in the housing adapted to cooperate with the connectors in the proximal component to provide a selective signal path between the proximal and the distal components. An electrical or optical lead is in communication with the data pin on the memory device when the proximal and distal components are engaged.
In accordance with another aspect of the present invention, the memory device includes a programmable read only memory internally configured to store a coil name.
In accordance with another aspect of the present invention, the a programmable read only memory includes exactly one data pin and exactly one ground pin.
In accordance with another aspect of the present invention, the data attributes associated with the imaging coil include coil bias patterns for selected modes of coil operation.
In accordance with another embodiment of the present invention, a method of manufacturing a magnetic resonance imaging coil includes connecting a memory device capable of storing a plurality of data attributes to the magnetic resonance imaging coil. The method further includes storing data attributes associated with the magnetic resonance imaging coil in the memory device.
In accordance with another aspect of the present invention, the coil mechanically connects to a magnetic resonance imaging system via a coil-side mating element connectable to an MR-side mating element. The method further includes disposing the memory device in the coil-side mating element.
In accordance with another aspect of the present invention, the disposing step includes electrically connecting a ground pin from the memory device to a conductive connector disposed in the coil side mating element. A path to ground is selectively established via an associated connector in the MR-side mating element.
In accordance with another aspect of the present invention, the disposing step further includes positioning a data pin from the memory element within the connector. A data path is then selectively established via an associated data lead in the MR-side mating element.
In accordance with another aspect of the present invention, the method further includes loading a coil name into a determined location in the memory device.
In accordance with another aspect of the present invention, representative currents and voltages for different channels supported by the coil are loaded into determined locations within the memory device.
In accordance with another embodiment of the present invention, a magnetic resonance imaging coil for selective operable connection to a magnetic resonance scanner includes a radio frequency antenna for at least receiving RF signals. A memory device stores data attributes associated with the radio frequency antenna.
In accordance with another aspect of the present invention, a coil-side mating element in communication with the radio frequency windings provides selective mechanical and data association with a corresponding mating element.
In accordance with another aspect of the present invention, the memory device includes an EEPROM.
In accordance with another aspect of the present invention, the EEPROM is disposed on the coil-side mating element.
In accordance with another aspect of the present invention, the EEPROM includes exactly one data pin and exactly one ground pin.
In accordance with another aspect of the present invention, the stored data attributes include a coil name.
In accordance with another aspect of the present invention, the stored data attributes include representative currents and voltages for channels associated with the magnetic resonance imaging coil.
In accordance with another aspect of the present invention, the stored data attributes include representative modes, associated bias patterns, and valid receive signal patterns associated with the magnetic resonance imaging coil.
One advantage of the present invention resides in the relatively large number of ID codes possible.
Another advantage of the present invention resides in the coil-side storage of coil attribute information.
Yet another advantage resides in the ability to introduce new coils and/or new functionality without having to update MR-side software.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.